72105709 has 6 divisors (see below), whose sum is σ = 78079146. Its totient is φ = 66558960.

The previous prime is 72105697. The next prime is 72105731. The reversal of 72105709 is 90750127.

It can be written as a sum of positive squares in 3 ways, for example, as 956484 + 71149225 = 978^2 + 8435^2 .

It is not a de Polignac number, because 72105709 - 2⁷ = 72105581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72105739) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 213162 + ... + 213499.

It is an arithmetic number, because the mean of its divisors is an integer number (13013191).

Almost surely, 2^72105709 is an apocalyptic number.

It is an amenable number.

72105709 is a deficient number, since it is larger than the sum of its proper divisors (5973437).

72105709 is a wasteful number, since it uses less digits than its factorization.

72105709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426687 (or 426674 counting only the distinct ones).

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 72105709 is about 8491.5080521660. The cubic root of 72105709 is about 416.2202609612.

The spelling of 72105709 in words is "seventy-two million, one hundred five thousand, seven hundred nine".